Chromatography Forum

Hi all,

We have never used 1.8 micron RP columns. Have you got any ideas about how many runs we can use this kind columns and how is it compared to conventional columns (5um) in life span aspect ?

Thanks.

Since it appears you are used to 5um, I would suggest looking at 3um before making the leap down to 2um.
With 3um, you can decrease your run time in half and pressure is acceptable for conventional HPLC systems:

http://www.imtaktusa.com/site_media/fil ... TI015E.pdf

We have been using 1.7 um columns for 5 years now, and some of them are still ok after more than 2000 injections in terms of pressure and efficiency.

We have been using 1.7 um columns for 5 years now, and some of them are still ok after more than 2000 injections in terms of pressure and efficiency.

Thank you both and as Gaetan Glauser said, 1.8um columns can be comparable with conventional columns in the durability. Is that right?.

Yes, at least from our experience. We analyse dirty plant samples among others, and we are quite suprised about column life span.

But as Bryan said, there is no point in using 1.7 or 1.8 um columns if your system cannot withstand high pressures. If you have a 400 bars system, better use 3.5 um, or 2.6 um fused core columns. Fused core technology provides about 80% of the 1.7 um efficiency, with 50% less pressure.

In general, the smaller the pariticle, the more easily the column is clogged due to the junks in the sample and/or mobile phase. Although some reported long lifetime of sub-micron columns, others complained about shorter column life for real-life samples. I tested a couple of 1.8-micron columns last year, and for no obvious reason, columns developed high pressure within two weeks and 100 injections of the standard. I believe with the same degree of care, larger particle columns (5-micron) have longer life time than sub-2-micron ones.

It all depends on what you are injecting and how many times...

I primarily use protein crashes for extractions and run 150 injections per night. Columns last 1,500 - 2,000 injections for me...

we are also using 1.8 michron column science 2-3 years but the main problem is the back pressure it is between 4000 to 4500 psi when u are using 1 or 1.2 ml flow . SO on time being it require special care also.
But there is no doubt it is helpful for reduce the analysis time and solvent.
If u use UPLC use of such column is more effective.

Filter, filter, filter!

Smaller particles = smaller frit pore size and smaller holes between the particles. It is possible that many of the pressure problems with these columns occurred because the solutions were only filtered to 0.45 um, rather than 0.2 or 0.1 um.

And, of course, "garbage in, garbage out" when it comes to samples.

I am also agree with mbicking. Filtration of mobile phase is must.

praveen